Buprenorphine Formulation Comparison: Tablet vs. Liquid. The partial opiate agonist buprenorphine is under intense study as an added pharmacotherapy for opiate addiction. Mounting empirical evidence suggests that it is both safe and efficacious, and a New Drug Application is anticipated soon. However, virtually all the clinical evidence for buprenorphine's safety and efficacy in opiate addiction treatment has been based on studies using a liquid formulation which, while well- absorbed sublingually, is cumbersome to administer and discoloration develops with prolonged storage. A sublingual tablet is being formulated for final market release. it is necessary to compare the tablet formulation to the liquid formulation before meaningful extrapolation of the existing data and -dosing recommendations can be made. This study proposes to compare the two formulations in terms of their respective bioavailability, clinical efficacy and patient acceptance. One-hundred- fifty opiate addicts meeting DSM-IV criteria for opiate dependence will be randomly assigned in equal numbers to an active tablet buprenorphine and liquid buprenorphine group, under double-blind, double-dummy conditions, and treated for 12 weeks followed by a four week crossover. The groups will be compared with respect to 1.) treatment outcome, 2.) serum blood level, and 3.) patient acceptance. A subgroup of 12 subjects will provide frequent blood samples for a full pharmacokinetic study. Results of this study will be of significant interest to the addiction treatment and research community. It will help determine if the efficacy established with sublingual liquid buprenorphine can be generalized to the tablet formulation and what dosing recommendations are appropriate.